This study examines associations between leisure reading and reading skills in data of 2,525 students followed from age 7 to 16. As a step further from traditional cross-lagged analysis, a random intercept cross-lagged panel model was used to identify within-person associations of leisure reading (books, magazines, newspapers, and digital reading), reading fluency, and reading comprehension. In Grades 1-3 poorer comprehension and fluency predicted less leisure reading. In later grades more frequent leisure reading, particularly of books, predicted better reading comprehension. Negative associations were found between digital reading and reading skills. The findings specify earlier findings of correlations between individuals by showing that reading comprehension improvement, in particular, is predicted by within-individual increases in book reading.